Perfume additives make laundry compositions more aesthetically pleasing to the consumer, and in some cases the perfume imparts a pleasant fragrance to fabrics treated therewith. The amount of perfume carryover from an aqueous laundry bath onto fabrics, however, is often marginal. By encapsulating perfume additives in microcapsules, the delivery efficiency and active lifetime of the perfume additives can be improved. Microcapsules provide several advantages, such as protecting the perfumes from physical or chemical reactions with incompatible ingredients in the laundry composition, and from volatilization or evaporation. Microcapsules can be particularly effective in the delivery and preservation of perfumes in that perfumes can be delivered to and retained within the fabric by a microcapsule that only ruptures, and therefore releases the perfume, when the fabric is dry. The rupture of microcapsules can be induced by various factors such as temperature so that the contents are delivered when the capsule degrades. Alternatively the microcapsules can be compromised by physical forces, such as crushing, or other methods that compromise the integrity of the microcapsules. Additionally, the microcapsule contents may be delivered via diffusion through the capsule wall during a desired time interval.
Scent associated with laundered laundry is important to many consumers. There are many so called “touch points” that consumers associate with during the laundry experience. Non-limiting examples of these touch points include the freshness experience associated with opening a fabric care container, opening a washing machine after washing laundry, opening a laundry dryer after drying laundry, and freshness associated with wearing laundered clothes. It has been reported that there is a significant portion of consumers that will fold and put away their laundry about one day after having laundered laundry. Freshness while folding laundry about one day after having laundered laundry also signals to the consumer that the laundry is clean.
Several compositions have been proposed to provide fragrances at various “touch points” of the laundering process. For example, WO 2011/094681 discloses fabric softening compositions comprising two different encapsulated perfume compositions to provide an improved laundry experience to consumers. These two different encapsulated perfume compositions each contains a specific mix of perfume ingredients having a boiling point (at standard pressure) greater than 250° C. and perfume ingredients having a boiling point lower than 250° C.
Instead of using two different encapsulated perfume compositions, WO 2011/075353 discloses a liquid detergent composition comprising a single type of perfume microcapsules which contains two different perfume raw materials, with one having a boiling point less than 250° C. and the other having a boiling point greater than 250° C.
It has been shown that the boiling point of a perfume ingredient, which is frequently used as an indication for its volatilization rate, does not correlate with its odor threshold concentration, i.e., the lowest concentration of the perfume ingredient that is perceivable by the human sense of smell. Therefore, selection of perfume ingredients based only on physical properties such as boiling points does not always provide the desired effect.
Thus, there is a need in the industry for compositions comprising perfume ingredients having different biological properties such as odor threshold concentrations, which release perfumes at the right level for the desired duration and time points during the laundering process to provide consumers with a delightful experience. There is also a need to improve the perfume release or diffusion in personal care applications. The present invention satisfies this and other needs of the industry.